The invention concerns two-component adhesives based on compounds containing ethylenic double bonds that are mixed with certain organoboron compounds as initiators, which can be handled in air and do not ignite spontaneously.
Adhesives that harden by polymerization of compounds containing ethylenic double bonds have been known for a long time. These can be prepared from methacrylic acid esters or acrylic acid esters of various alcohols with the addition of peroxides or hydroperoxides, as initiators, and additional adjuvants. Besides these, adhesive agents and filling agents are known for dental medical or surgical uses that contain as an essential component trialkyl boron compounds, such as triethylboron, tri-n-butylboron, etc., in addition to acrylates or methacrylates and other reaction partners containing ethylenic double bonds. Such trialkyl boron compounds, however, have the disadvantage that they are readily flammable so that the handling of these adhesives causes considerable difficulties. An attempt to correct this problem has been made in that one can react the trialkyl boron compounds with 0.3 to 0.9 mols of oxygen. In addition, trialkyl boron compounds were also reacted with amines to reduce the spontaneous combustion. With these steps, the ignition temperture is shifted within a range of from 0.degree. to 75.degree. C., but a considerable uncertainty remains in the handling of such mixtures. In particular, they are not suitable for construction bonding.